Film projector film gate



Jan. 22, 1963 J. J. KOTTE ETAL 3,074,310 FILM PROJECTOR FILM GATE FiledJune 29, 1959 l u 3 i7 44 -e 7 Q as INVENTORS JAN JACOB KOTTE ERIKNETTEN United States Patent ()fiice 3,074,310 FILM ERGJECTGR FKLM GATEJan Jacob Kotte and Erik Netten, Eindhoven, Netherlands, assignors toNorth American Philips (Company, Inc., New York, N.Y., a corporation ofDelaware Fiied June 29, 1959, Ser. No. 823,379 Claims priority,application Netherlands Aug. 14, 1953 4 Ciaims. (til. 83-17) The presentinvention relates to a device used in film projectors and moreparticularly to a guide arrangement for the film strip in the area ofthe film gate.

In known structures of the above-mentioned kind, the guide elements arefixedly rranged on one side of the film in order to obtain a fixed pointof orientation of the film with respect to the projection aperture.

According to the teachings of the invention however, the film guideelements are also resiliently arranged on both sides of the film, butare subject to a spring pressure higher on one side than that on theother side thereof.

The structure according to the invention allords the advantage that theguide elements which are subject to a higher spring pressure do notchange their positions during operation, so that the film still has afixed point of orientation with respect to the projection aperture,while the structure, the securement and the arrangement of the guideelements may be wholly identical, thus enabling the guide elements to bechanged in a simple man ner and also interchanged.

Another object of the present invention is to provide guide elementscomprising apertured discs which are urged against the film or, in theabsence of a film, against fixed stops by means of resiliently arrangedpins having their pointed ends extending in part into the holes of thediscs.

The resiliently arranged pins maintain the guide discs in their mountedpositions. The discs may be removed from the device in a very simplemanner by moving them against the spring pressure and they may either bereplaced, if desired, or interchanged, or turned by 180 about adiametric axis and mounted again.

According to a further feature or" the invention, the discs, pins,springs and holders are preferably Wholly identical on each side of thefilm, the springs on one side of the film being subject to a tensiongreater than that on the other side of the film.

In order that the invention may be readily carried into efiect, oneembodiment thereof will now be described in detail by way of example,with reference to the accompanying drawing, in which the sole figure isa front elevation view of a film track according to the invention.

Referring to the drawing, the present device illustrates a projectionaperture 1 having a transverse guide means for the film comprisingceramic discs 2, 3, 4 and 5 which are urged against fixed stops 10, 11,12 and 13 by means of resiliently mounted pins 6, 7, 8 and 9. Discs ofceramic material have been found to be more resistant to wear. Thepointed extremities of the pins 6, '7, 8 and 9 extend into the centralapertures of the discs. The pins 6, 7, 8 and 9 are hollow, andaccommodate coil springs, only the two upper ones i -l, 15 being visiblein the drawing. The figure shows that the spring 14 is subject to ahigher tension than applied to spring 15. It is thus ensured that aftera film has been inserted in the guide means that the 3,074,310 PatentedJan. 22, 1963 discs 2 and d are maintained in engagement with the fixedstops i0 and 12 so that these discs fulfil the function of fixed stopsfor the film. The discs 3 and 5 on the other hand may be moved by thefilm away from their fixed stops i1 and 13 against the action of thesprings under low tension. The discs 2, 3, 4, and 5, the pins 6, 7, 8and 9, the springs 1 and 1.5 and the structure of the holders l6 and 17are identical. This, of course, offers the advantage ofinterchangeability of the parts.

What is claimed is:

l. A film device having a film track with a projection aperturecomprising a plurality of guide elements acting on the edges of the filmto be guided, means resiliently mounting said guide elements on eachside of said projection aperture, the resilient force acting against theguide elements in the direction of the film width and being greater onone side of said film aperture than the resilient force acting againstthe guide elements on the other side of said film aperture whereby theguide elements having the greater resilient force act as fixed stops forthe film.

2. A film device having a film track with a projection aperturecomprising a plurality of apertured guide elements, means resilientlymounting said guide elements on each side of said projection aperture,the resilient force acting against the guide elements on one side ofsaid film aperture being greater than the resilient force acting againstthe guide elements on the other side of said guide aperture, saidresilient mounting means for said guide elements including a pluralityof pins, spring means urging said pins against said guide elements, oneend of each pin extending through at least part of the aperture of theassociated guide element.

3. A film device as claimed in claim 2 wherein said pins, springs andguide elements are identical, the springs on one side of said projectionaperture being compressed to a greater extent than the springs on theother side of said aperture.

4. A film device having a film track with a projection aperturecomprising a plurality of guide elements each including a ceramic dischaving a centrally located aperture, means resiliently mounting saidguide elements on each side of said projection aperture, the resilientforce acting against the guide elements on one side of said filmaperture being greater than the resilient force acting against the guideelements on the other side of said film aperture whereby the guideelements having the greater resilient force act as fixed stops for thefilm.

References Cited in the file of this patent UNITED STATES PATENTS1,437,895 Horst Dec. 5, 1922 1,781,945 Case Nov. 18, 1930 1,854,004Tschopp Apr. 12, 1932 2,002,074 Bassoon May 21, 1935 2,120,249 HolmanJune 14, 1938 2,142,606 Debrie Jan. 3, 1939 2,368,634 Boecking Feb. 6,1945 2,534,732 Perillo Dec. 19, 1950 FOREIGN PATENTS 537,406 GermanyNov. 2, 1931 532,658 Germany Aug. 21, 1933

1. A FILM DEVICE HAVING A FILM TRACK WITH A PROJECTION APERTURECOMPRISING A PLURALITY OF GUIDE ELEMENTS ACTING ON THE EDGES OF THE FILMTO BE GUIDED, MEANS RESILIENTLY MOUNTING SAID GUIDE ELEMENTS ON EACHSIDE OF SAID PROJECTION APERTURE, THE RESILIENT FORCE ACTING AGAINST THEGUIDE ELEMENTS IN THE DIRECTION OF THE FILM WIDTH AND BEING GREATER ONONE SIDE OF SAID FILM APERTURE THAN THE RESILIENT FORCE ACTING AGAINSTTHE GUIDE ELEMENTS ON THE OTHER SIDE OF SAID FILM APERTURE WHEREBY THEGUIDE ELEMENTS HAVING THE GREATER RESILIENT FORCE ACT AS FIXED STOPS FORTHE FILM.